验证码功能的两种实现方式

绝大部分应用都会有验证码这个功能，这个功能与业务无关，是可复用的。

servlet方式

1. web.xml中加入一个servlet

<!-- spring的servlet -->
<servlet>
<servlet-name>springServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
<multipart-config>
<max-file-size>52428800</max-file-size>
<max-request-size>52428800</max-request-size>
<file-size-threshold>0</file-size-threshold>
</multipart-config>
</servlet>
<servlet-mapping>
<servlet-name>springServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!-- 验证码的servlet -->
<servlet>
<servlet-name>CaptchaServlet</servlet-name>
<servlet-class>com.kylin.drugmng.servlet.CaptchaServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>CaptchaServlet</servlet-name>
<url-pattern>/CaptchaServlet</url-pattern>
</servlet-mapping>

1. CapchaServlet.java

public class CaptchaServlet extends HttpServlet {
private static final long serialVersionUID = 7301233141618834332L;
public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
response.setContentType("image/jpeg");
//生成随机字串

String verifyCode = CaptchaUtils.generateVerifyCode(4);
//存入会话session

HttpSession session = request.getSession(true);
session.setAttribute("captchaRand", verifyCode.toLowerCase());
//生成图片

int w = 200, h = 80;
CaptchaUtils.outputImage(w, h, response.getOutputStream(), verifyCode);
}
}

1. login.jsp

<span>
<img id="captchaImg" style="height: 57px; width: 129px;" src="CaptchaServlet">
</span>

controller实现

1. loginController.java

@Controller
@RequestMapping("/login/")
public class LoginController {
//获取验证码
@RequestMapping("drawcheckcode")
@ResponseBody
public void drawCheckCode(HttpServletResponse resp, HttpSession session) throws IOException {
resp.setContentType("image/jpg");
int width = 70;
int height = 25;
Captcha c = Captcha.getInstance();
c.set(width, height);
String checkcode = c.generateCheckcode();
// 验证码放入session
session.setAttribute("cCode", checkcode);
OutputStream os = resp.getOutputStream();
ImageIO.write(c.generateCheckImg(checkcode), "jpg", os);
}
//验证码验证
@RequestMapping("login")
public ModelAndView login(String account, String password, String checkcode,
HttpSession session) {
// session.setMaxInactiveInterval(20);
ModelAndView mav = null;
PageData pd = new PageData();
// 获取session中的验证码
String cCode = (String) session.getAttribute("cCode");
log.info("用户输入的验证码是：" + checkcode + "，内存中保存的验证码是：" + cCode);
// 验证码为null则跳转登录界面
if (checkcode == null) {
mav = new ModelAndView("login");
}
else if (!checkcode.equalsIgnoreCase(cCode)) {// 比对验证码，忽视大小写。验证码错误则返回登录界面
pd.setSuccess(false);
pd.setMessage("验证码错误");
mav = new ModelAndView("login");
mav.addObject("pd", pd);
}
return mav;
}
}

2.login.htm

<img id="captchaimage" class="sureImage"
src="/user/drawcheckcode.htm" onclick="reCheckcode(this)" />

验证码工具类

CaptchaUtils.java

public class CaptchaUtils {
// 使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
public static final String VERIFY_CODES = "23456789ABCDEFGHJKLMNPQRSTUVWXYZ";
private static Random random = new Random();
/**
* 使用系统默认字符源生成验证码
*
* @param verifySize
*
验证码长度
* @return
*/
public static String generateVerifyCode(int verifySize) {
return generateVerifyCode(verifySize, VERIFY_CODES);
}
/**
* 使用指定源生成验证码
*
* @param verifySize
*
验证码长度
* @param sources
*
验证码字符源
* @return
*/
public static String generateVerifyCode(int verifySize, String sources) {
if (sources == null || sources.length() == 0) {
sources = VERIFY_CODES;
}
int codesLen = sources.length();
Random rand = new Random(System.currentTimeMillis());
StringBuilder verifyCode = new StringBuilder(verifySize);
for (int i = 0; i < verifySize; i++) {
verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
}
return verifyCode.toString();
}
/**
* 生成随机验证码文件,并返回验证码值
*
* @param w
* @param h
* @param outputFile
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException {
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, outputFile, verifyCode);
return verifyCode;
}
/**
* 输出随机验证码图片流,并返回验证码值
*
* @param w
* @param h
* @param os
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, OutputStream os, int verifySize) throws IOException {
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, os, verifyCode);
return verifyCode;
}
/**
* 生成指定验证码图像文件
*
* @param w
* @param h
* @param outputFile
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, File outputFile, String code) throws IOException {
if (outputFile == null) {
return;
}
File dir = outputFile.getParentFile();
if (!dir.exists()) {
dir.mkdirs();
}
try {
outputFile.createNewFile();
FileOutputStream fos = new FileOutputStream(outputFile);
outputImage(w, h, fos, code);
fos.close();
} catch (IOException e) {
throw e;
}
}
/**
* 输出指定验证码图片流
*
* @param w
* @param h
* @param os
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, OutputStream os, String code) throws IOException {
int verifySize = code.length();
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Random rand = new Random();
Graphics2D g2 = image.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Color[] colors = new Color[5];
Color[] colorSpaces = new Color[] { Color.WHITE, Color.CYAN, Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA,
Color.ORANGE, Color.PINK, Color.YELLOW };
float[] fractions = new float[colors.length];
for (int i = 0; i < colors.length; i++) {
colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
fractions[i] = rand.nextFloat();
}
Arrays.sort(fractions);
g2.setColor(Color.GRAY);// 设置边框色
g2.fillRect(0, 0, w, h);
Color c = getRandColor(200, 250);
g2.setColor(c);// 设置背景色
g2.fillRect(0, 2, w, h - 4);
// 绘制干扰线
Random random = new Random();
g2.setColor(getRandColor(160, 200));// 设置线条的颜色
for (int i = 0; i < 20; i++) {
int x = random.nextInt(w - 1);
int y = random.nextInt(h - 1);
int xl = random.nextInt(6) + 1;
int yl = random.nextInt(12) + 1;
g2.drawLine(x, y, x + xl + 40, y + yl + 20);
}
// 添加噪点
float yawpRate = 0.05f;// 噪声率
int area = (int) (yawpRate * w * h);
for (int i = 0; i < area; i++) {
int x = random.nextInt(w);
int y = random.nextInt(h);
int rgb = getRandomIntColor();
image.setRGB(x, y, rgb);
}
shear(g2, w, h, c);// 使图片扭曲
g2.setColor(getRandColor(100, 160));
int fontSize = h - 4;
Font font = new Font("Algerian", Font.ITALIC, fontSize);
g2.setFont(font);
char[] chars = code.toCharArray();
for (int i = 0; i < verifySize; i++) {
AffineTransform affine = new AffineTransform();
affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1),
(w / verifySize) * i + fontSize / 2, h / 2);
g2.setTransform(affine);
g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
}
g2.dispose();
ImageIO.write(image, "jpg", os);
}
private static Color getRandColor(int fc, int bc) {
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
private static int getRandomIntColor() {
int[] rgb = getRandomRgb();
int color = 0;
for (int c : rgb) {
color = color << 8;
color = color | c;
}
return color;
}
private static int[] getRandomRgb() {
int[] rgb = new int[3];
for (int i = 0; i < 3; i++) {
rgb[i] = random.nextInt(255);
}
return rgb;
}
private static void shear(Graphics g, int w1, int h1, Color color) {
shearX(g, w1, h1, color);
shearY(g, w1, h1, color);
}
private static void shearX(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(2);
boolean borderGap = true;
int frames = 1;
int phase = random.nextInt(2);
for (int i = 0; i < h1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
g.copyArea(0, i, w1, 1, (int) d, 0);
if (borderGap) {
g.setColor(color);
g.drawLine((int) d, i, 0, i);
g.drawLine((int) d + w1, i, w1, i);
}
}
}
private static void shearY(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(40) + 10; // 50;
boolean borderGap = true;
int frames = 20;
int phase = 7;
for (int i = 0; i < w1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
g.copyArea(i, 0, 1, h1, 0, (int) d);
if (borderGap) {
g.setColor(color);
g.drawLine(i, (int) d, i, 0);
g.drawLine(i, (int) d + h1, i, h1);
}
}
}
public static void main(String[] args) throws IOException {
File dir = new File("F:/verifies");
int w = 200, h = 80;
for (int i = 0; i < 50; i++) {
String verifyCode = generateVerifyCode(4);
File file = new File(dir, verifyCode + ".jpg");
outputImage(w, h, file, verifyCode);
}
}

Captcha.java

public class Captcha {
private int width;
private int height;
private int num;
private String code;
private static final Random ran = new Random();
private static Captcha captcha;
private Captcha(){
//code = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
code="01abcde23fghi45jkmnpqrstu67vwxyz89";
num = 4;
}
public static Captcha getInstance() {
if(captcha==null) captcha = new Captcha();
return captcha;
}
public void set(int width,int height,int num,String code) {
this.width = width;
this.height = height;
this.setNum(num);
this.setCode(code);
}
public void set(int width,int height) {
this.width = width;
this.height = height;
}
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
public String getCode() {
return code;
}
public void setCode(String code) {
this.code = code;
}
public String generateCheckcode() {
StringBuffer cc = new StringBuffer();
for(int i=0;i<num;i++) {
cc.append(code.charAt(ran.nextInt(code.length())));
}
return cc.toString();
}
public BufferedImage generateCheckImg(String checkcode) {
//创建一个图片对象
BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
//获取图片对象的画笔
Graphics2D graphic = img.createGraphics();
graphic.setColor(Color.WHITE);
graphic.fillRect(0, 0, width, height);
graphic.setColor(Color.BLACK);
graphic.drawRect(0, 0, width-1, height-1);
Font font = new Font("宋体",Font.BOLD+Font.ITALIC,(int)(height*0.8));
graphic.setFont(font);
for(int i=0;i<num;i++) {
graphic.setColor(new Color(ran.nextInt(180),ran.nextInt(180),ran.nextInt(180)));
graphic.drawString(String.valueOf(checkcode.charAt(i)), i*(width/num)+4, (int)(height*0.8));
}
//加一些点
for(int i=0;i<(width+height);i++) {
graphic.setColor(new Color(ran.nextInt(255),ran.nextInt(255),ran.nextInt(255)));
graphic.drawOval(ran.nextInt(width), ran.nextInt(height), 1, 1);
}
//加一些线
//for(int i=0;i<4;i++) {
//
graphic.setColor(new Color(ran.nextInt(255),ran.nextInt(255),ran.nextInt(255)));
//
graphic.drawLine(0, ran.nextInt(height), width, ran.nextInt(height));
//}
return img;
}

最后

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